Revascularization restores blood flow in vessels by either going around or going through an occlusion that is restricting flow. A bypass graft redirects a supply of blood upstream of the occlusion site, around the occlusion, and delivers it to a site downstream of the occlusion site. Highly evasive surgery, conducted by cutting from outside the body to reach the site where the bypass graft is placed, is used to place a bypass graft. Existing percutaneous methods of revascularization, thus, go through the occlusion rather than around it.
Percutaneous entry to reach occluded arteries in the body is accomplished at locations where an artery is close to the surface of the skin, e.g., in the femoral artery of the groin. When the femoral artery is being accessed, a guiding catheter is inserted in the femoral artery and advanced toward either the coronary or peripheral arteries. The device(s) for accomplishing revascularization are then advanced through the guiding catheter and to the site of the occlusion by a practitioner. A common device for opening an occlusion is a balloon on a catheter, advanced through the guiding catheter, then entering the occlusion and being inflated to push the occlusion open. A more recent technique adds a bare or drug-eluting stent of wire mesh around the balloon to keep the occluded area propped open after the balloon is removed. The guiding catheter may also be used as the passageway for advancing devices other than balloons and stents that are used for removing an occlusion. These devices generally include mechanical and electrical means for removing calcified, thrombus-filled, or other types of occlusions within the vessel.